docs(keycloak-session-store): import the session-storage lab as a new project

The keycloak project ended with four open questions that design could not
settle. A two-VM lab was built to answer them by measurement, and this is
that material: 26 experiments, 125 raw command outputs, 22 browser captures.

Follows the import procedure in README.md.

  source/     the originating repository verbatim — 78 documents, 28 SVGs,
              8 manifests, plus .source-revision recording the commit
  final/      the SSOT
    document.md   729 lines written from the 29 experiment documents, not
                  concatenated: what was predicted, what was measured, and
                  where the measurement itself was wrong
    evidence/raw    125 outputs, flattened to <experiment>__<file> because
                    the originals collided (01-baseline.txt appeared three
                    times) and the audit only globs the top level
    evidence/meta   one per raw file; command and exitCode are null and the
                    README says why rather than inventing them
    evidence/browser  22 captures
    assets/       three diagrams through techviz
    .techviz/     their VizSpecs

A separate project rather than an addition to keycloak: the B-layer answers
that project's four questions, but the A, C and D layers are about cluster
failure, SSO and operations, and one document.md should hold one subject.
The four question records there can point here through 관계.

Recorded rather than papered over: only three of the 28 diagrams were
remade. The repository forbids hand-drawn SVG and forbids titles inside the
canvas; all 28 originals carry both, so converting them is redrawing, not
reformatting. They stay in source/ and the gap is written into the document.

verify-pipeline.py passes. audit-records.py reports no issues.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/clean-architecture-backend-template/final/evidence/raw/a-startup-probe-that-never-runs.txt

@@ -0,0 +1,70 @@
+# 탐침이 자기를 소개하는 문단
+/**
+ * Asks the server what it is, once, at startup.
+ *
+ * <p>Configuration says what the deployment intends; only the server says what is true. The version
+ * a managed Redis advertises does not imply the modules are present, and a replicated deployment's
+ * write durability is a server setting no client can compensate for. Both are cheap to ask and
+ * expensive to discover later — a missing capability found at the first request is an outage, found
+ * here it is a failed deploy.
+
+# 그것이 확인하는 넷
+    RedisCapabilities capabilities =
+        probe.probe(
+            serverFacts.version(),
+            settings.getMode(),
+            settings.getDatabase(),
+            commandPresence(serverFacts.commands()),
+            requiredCapabilities);
+    probe.requireWriteDurability(
+        settings.getMode(),
+        serverFacts.minReplicasToWrite(),
+        serverFacts.minReplicasMaxLagSeconds(),
+        settings.isAcknowledgedWriteLossAccepted());
+    return capabilities;
+  }
+
+
+# 넷째의 javadoc — 실측과 결론
+   * Refuses to start against a replicated deployment that cannot keep the writes it acknowledges.
+   *
+   * <p>This is the one server-side setting the SDK cannot compensate for. When a primary is
+   * superseded by a promotion it does not find out immediately, and until it does it keeps
+   * answering {@code +OK} to writes that are discarded when it resyncs from the new primary. The
+   * Sentinel lane measured eleven seconds and 2,086 acknowledged-then-discarded writes, with
+   * exactly one command failing. No client can see it: the server answered, so the driver, this
+   * SDK, and the caller all record a success. There is no metric to add, no failure to retry, and
+   * no certainty value that describes it.
+   *
+   * <p>{@code min-replicas-to-write} with a bounded {@code min-replicas-max-lag} is what turns that
+   * into a {@code NOREPLICAS} refusal the caller can act on — the same promotion then lost one
+   * write instead of 2,086. So a replicated deployment without it is a startup failure rather than
+   * a warning, on the same principle as every other guardrail here: a setting that makes a
+   * guarantee meaningless stops the context instead of degrading quietly.
+#   그리고 검사가 두 겹인 이유
+   * <p>Both halves of the guarantee are checked. A replica count on its own decides only how many
+   * replicas must be <em>connected</em>; how far behind they may be is {@code
+   * min-replicas-max-lag}, and Redis treats {@code 0} there as "no lag requirement". A deployment
+   * with {@code min-replicas-to-write 2} and {@code min-replicas-max-lag 0} therefore accepts a
+   * write once two arbitrarily stale replicas are attached, which is the same lost-write exposure
+   * the count was supposed to remove. Checking the count alone let that configuration pass while
+   * the failure message told the operator to set the lag bound.
+
+# 그 실패는 일어나지 않는다
+  두 탐침 밖에서 그것들을 언급하는 main 코드: 1
+RedisSdkSettings.java:888:   * signal exists for it; see {@link RedisCapabilityProbe#requireWriteDurability}.
+  confirm( 을 부르는 main 코드: 0
+
+# 자동설정이 만드는 빈
+85 public RedisSdkSettings redisSdkSettings() {
+102 public RedisSdkSettingsValidation redisSdkSettingsValidation(
+157 public RedisResolvedCredentials redisResolvedCredentials(
+227 public RedisRuntimeClient redisRuntimeClient(
+274 public RedisRuntimeOwner redisRuntimeOwner(RedisRuntimeClient client, RedisSdkSettings settings) {
+298 public HealthIndicator redisOptional(RedisRuntimeOwner owner, RedisSdkSettings settings) {
+326 public HealthIndicator redisRequired(RedisRuntimeOwner owner, RedisSdkSettings settings) {
+  그중 탐침: 0
+
+# 로직을 고정하는 테스트 케이스 수
+  RedisCapabilityProbeTest: 11
+  RedisStartupProbeTest: 7